/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
 * Copyright (C) Terry Dawson VK2KTJ (terry@animats.net)
 * Copyright (C) Tomi Manninen OH2BNS (oh2bns@sral.fi)
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/stat.h>
#include <net/net_namespace.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <linux/fcntl.h>
#include <linux/termios.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <net/rose.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/tcp_states.h>
#include <net/ip.h>
#include <net/arp.h>

static int rose_ndevs = 10;

int sysctl_rose_restart_request_timeout = ROSE_DEFAULT_T0;
int sysctl_rose_call_request_timeout    = ROSE_DEFAULT_T1;
int sysctl_rose_reset_request_timeout   = ROSE_DEFAULT_T2;
int sysctl_rose_clear_request_timeout   = ROSE_DEFAULT_T3;
int sysctl_rose_no_activity_timeout     = ROSE_DEFAULT_IDLE;
int sysctl_rose_ack_hold_back_timeout   = ROSE_DEFAULT_HB;
int sysctl_rose_routing_control         = ROSE_DEFAULT_ROUTING;
int sysctl_rose_link_fail_timeout       = ROSE_DEFAULT_FAIL_TIMEOUT;
int sysctl_rose_maximum_vcs             = ROSE_DEFAULT_MAXVC;
int sysctl_rose_window_size             = ROSE_DEFAULT_WINDOW_SIZE;

static HLIST_HEAD(rose_list);
static DEFINE_SPINLOCK(rose_list_lock);

static const struct proto_ops rose_proto_ops;

ax25_address rose_callsign;

/*
 * ROSE network devices are virtual network devices encapsulating ROSE
 * frames into AX.25 which will be sent through an AX.25 device, so form a
 * special "super class" of normal net devices; split their locks off into a
 * separate class since they always nest.
 */
static struct lock_class_key rose_netdev_xmit_lock_key;
static struct lock_class_key rose_netdev_addr_lock_key;

static void rose_set_lockdep_one(struct net_device *dev,
				 struct netdev_queue *txq,
				 void *_unused)
{
	lockdep_set_class(&txq->_xmit_lock, &rose_netdev_xmit_lock_key);
}

static void rose_set_lockdep_key(struct net_device *dev)
{
	lockdep_set_class(&dev->addr_list_lock, &rose_netdev_addr_lock_key);
	netdev_for_each_tx_queue(dev, rose_set_lockdep_one, NULL);
}

/*
 *	Convert a ROSE address into text.
 */
char *rose2asc(char *buf, const rose_address *addr)
{
	if (addr->rose_addr[0] == 0x00 && addr->rose_addr[1] == 0x00 &&
	    addr->rose_addr[2] == 0x00 && addr->rose_addr[3] == 0x00 &&
	    addr->rose_addr[4] == 0x00) {
		strcpy(buf, "*");
	} else {
		sprintf(buf, "%02X%02X%02X%02X%02X", addr->rose_addr[0] & 0xFF,
						addr->rose_addr[1] & 0xFF,
						addr->rose_addr[2] & 0xFF,
						addr->rose_addr[3] & 0xFF,
						addr->rose_addr[4] & 0xFF);
	}

	return buf;
}

/*
 *	Compare two ROSE addresses, 0 == equal.
 */
int rosecmp(rose_address *addr1, rose_address *addr2)
{
	int i;

	for (i = 0; i < 5; i++)
		if (addr1->rose_addr[i] != addr2->rose_addr[i])
			return 1;

	return 0;
}

/*
 *	Compare two ROSE addresses for only mask digits, 0 == equal.
 */
int rosecmpm(rose_address *addr1, rose_address *addr2, unsigned short mask)
{
	unsigned int i, j;

	if (mask > 10)
		return 1;

	for (i = 0; i < mask; i++) {
		j = i / 2;

		if ((i % 2) != 0) {
			if ((addr1->rose_addr[j] & 0x0F) != (addr2->rose_addr[j] & 0x0F))
				return 1;
		} else {
			if ((addr1->rose_addr[j] & 0xF0) != (addr2->rose_addr[j] & 0xF0))
				return 1;
		}
	}

	return 0;
}

/*
 *	Socket removal during an interrupt is now safe.
 */
static void rose_remove_socket(struct sock *sk)
{
	spin_lock_bh(&rose_list_lock);
	sk_del_node_init(sk);
	spin_unlock_bh(&rose_list_lock);
}

/*
 *	Kill all bound sockets on a broken link layer connection to a
 *	particular neighbour.
 */
void rose_kill_by_neigh(struct rose_neigh *neigh)
{
	struct sock *s;

	spin_lock_bh(&rose_list_lock);
	sk_for_each(s, &rose_list) {
		struct rose_sock *rose = rose_sk(s);

		if (rose->neighbour == neigh) {
			rose_disconnect(s, ENETUNREACH, ROSE_OUT_OF_ORDER, 0);
			rose->neighbour->use--;
			rose->neighbour = NULL;
		}
	}
	spin_unlock_bh(&rose_list_lock);
}

/*
 *	Kill all bound sockets on a dropped device.
 */
static void rose_kill_by_device(struct net_device *dev)
{
	struct sock *s;

	spin_lock_bh(&rose_list_lock);
	sk_for_each(s, &rose_list) {
		struct rose_sock *rose = rose_sk(s);

		if (rose->device == dev) {
			rose_disconnect(s, ENETUNREACH, ROSE_OUT_OF_ORDER, 0);
			rose->neighbour->use--;
			rose->device = NULL;
		}
	}
	spin_unlock_bh(&rose_list_lock);
}

/*
 *	Handle device status changes.
 */
static int rose_device_event(struct notifier_block *this, unsigned long event,
	void *ptr)
{
	struct net_device *dev = (struct net_device *)ptr;

	if (!net_eq(dev_net(dev), &init_net))
		return NOTIFY_DONE;

	if (event != NETDEV_DOWN)
		return NOTIFY_DONE;

	switch (dev->type) {
	case ARPHRD_ROSE:
		rose_kill_by_device(dev);
		break;
	case ARPHRD_AX25:
		rose_link_device_down(dev);
		rose_rt_device_down(dev);
		break;
	}

	return NOTIFY_DONE;
}

/*
 *	Add a socket to the bound sockets list.
 */
static void rose_insert_socket(struct sock *sk)
{

	spin_lock_bh(&rose_list_lock);
	sk_add_node(sk, &rose_list);
	spin_unlock_bh(&rose_list_lock);
}

/*
 *	Find a socket that wants to accept the Call Request we just
 *	received.
 */
static struct sock *rose_find_listener(rose_address *addr, ax25_address *call)
{
	struct sock *s;

	spin_lock_bh(&rose_list_lock);
	sk_for_each(s, &rose_list) {
		struct rose_sock *rose = rose_sk(s);

		if (!rosecmp(&rose->source_addr, addr) &&
		    !ax25cmp(&rose->source_call, call) &&
		    !rose->source_ndigis && s->sk_state == TCP_LISTEN)
			goto found;
	}

	sk_for_each(s, &rose_list) {
		struct rose_sock *rose = rose_sk(s);

		if (!rosecmp(&rose->source_addr, addr) &&
		    !ax25cmp(&rose->source_call, &null_ax25_address) &&
		    s->sk_state == TCP_LISTEN)
			goto found;
	}
	s = NULL;
found:
	spin_unlock_bh(&rose_list_lock);
	return s;
}

/*
 *	Find a connected ROSE socket given my LCI and device.
 */
struct sock *rose_find_socket(unsigned int lci, struct rose_neigh *neigh)
{
	struct sock *s;

	spin_lock_bh(&rose_list_lock);
	sk_for_each(s, &rose_list) {
		struct rose_sock *rose = rose_sk(s);

		if (rose->lci == lci && rose->neighbour == neigh)
			goto found;
	}
	s = NULL;
found:
	spin_unlock_bh(&rose_list_lock);
	return s;
}

/*
 *	Find a unique LCI for a given device.
 */
unsigned int rose_new_lci(struct rose_neigh *neigh)
{
	int lci;

	if (neigh->dce_mode) {
		for (lci = 1; lci <= sysctl_rose_maximum_vcs; lci++)
			if (rose_find_socket(lci, neigh) == NULL && rose_route_free_lci(lci, neigh) == NULL)
				return lci;
	} else {
		for (lci = sysctl_rose_maximum_vcs; lci > 0; lci--)
			if (rose_find_socket(lci, neigh) == NULL && rose_route_free_lci(lci, neigh) == NULL)
				return lci;
	}

	return 0;
}

/*
 *	Deferred destroy.
 */
void rose_destroy_socket(struct sock *);

/*
 *	Handler for deferred kills.
 */
static void rose_destroy_timer(unsigned long data)
{
	rose_destroy_socket((struct sock *)data);
}

/*
 *	This is called from user mode and the timers. Thus it protects itself
 *	against interrupt users but doesn't worry about being called during
 *	work.  Once it is removed from the queue no interrupt or bottom half
 *	will touch it and we are (fairly 8-) ) safe.
 */
void rose_destroy_socket(struct sock *sk)
{
	struct sk_buff *skb;

	rose_remove_socket(sk);
	rose_stop_heartbeat(sk);
	rose_stop_idletimer(sk);
	rose_stop_timer(sk);

	rose_clear_queues(sk);		/* Flush the queues */

	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
		if (skb->sk != sk) {	/* A pending connection */
			/* Queue the unaccepted socket for death */
			sock_set_flag(skb->sk, SOCK_DEAD);
			rose_start_heartbeat(skb->sk);
			rose_sk(skb->sk)->state = ROSE_STATE_0;
		}

		kfree_skb(skb);
	}

	if (sk_has_allocations(sk)) {
		/* Defer: outstanding buffers */
		setup_timer(&sk->sk_timer, rose_destroy_timer,
				(unsigned long)sk);
		sk->sk_timer.expires  = jiffies + 10 * HZ;
		add_timer(&sk->sk_timer);
	} else
		sock_put(sk);
}

/*
 *	Handling for system calls applied via the various interfaces to a
 *	ROSE socket object.
 */

static int rose_setsockopt(struct socket *sock, int level, int optname,
	char __user *optval, unsigned int optlen)
{
	struct sock *sk = sock->sk;
	struct rose_sock *rose = rose_sk(sk);
	int opt;

	if (level != SOL_ROSE)
		return -ENOPROTOOPT;

	if (optlen < sizeof(int))
		return -EINVAL;

	if (get_user(opt, (int __user *)optval))
		return -EFAULT;

	switch (optname) {
	case ROSE_DEFER:
		rose->defer = opt ? 1 : 0;
		return 0;

	case ROSE_T1:
		if (opt < 1)
			return -EINVAL;
		rose->t1 = opt * HZ;
		return 0;

	case ROSE_T2:
		if (opt < 1)
			return -EINVAL;
		rose->t2 = opt * HZ;
		return 0;

	case ROSE_T3: